Flexural behavior of natural fiber-reinforced foamed concrete beams

Climate change has become a worldwide problem, and many conventional construction materials contribute to carbon emissions. Therefore, the need for sustainable infrastructure has progressed with the increasing use of various plant-based natural fibers for structural applications. This study assesses the feasibility and performance of using natural fiber rope-based reinforcement in foamed concrete structures. The flexural behavior of foamed concrete beams reinforced with the roselle fiber rope-based reinforcement is investigated using finite element (FE) analysis-based numerical and code-based simplified analytical approaches. In the FE model, beams are discretized along the length and depth with a multi-fiber model approach. The nonlinear constitutive behavior of the concrete is taken as per the design standards, and the material properties of natural fiber-based reinforcement, i.e., roselle fiber and roselle fiber rope, are obtained experimentally. The bond-slip behavior between reinforcement and concrete is also implemented using Eligehausen’s law. Furthermore, the influence of the elastic modulus of the reinforcement, span length, and reinforcement ratio on the flexural capacity and deflection of the beams is investigated. The study provides an understanding of roselle fibers and roselle fiber rope in terms of tensile strengths and stiffness to explore their suitability as reinforcement materials. Moreover, it is shown that roselle fiber rope-based reinforcement increases the load-carrying capacity of reinforced foamed concrete beams by approximately 90% (depending upon the elastic modulus of the reinforcement) compared to plain foamed concrete beams. This significant improvement underscores the potential of roselle fiber ropes as an alternative to steel or synthetic fiber-based reinforcement in concrete beams subjected to relatively low-magnitude loads, providing a clear conclusion and recommendation based on the findings of the study.